Cars, at least American cars are so large because people want them that way. Yes there are some safety laws that require at some size and weight increases. But not much. My 2019 car isn't significantly larger or heavier than my 1992. It is larger and heavier(it also has some additional creature comforts) but the differences are fairly small. One of the issues, is the same reason crowded rooms get nosier. As cars get larger people want even larger cars, to see over and around and feel safer.